Transendoscopic implant capsule

ABSTRACT

An implant capsule for insertion into a body canal to apply radiation treatment to a selected portion of the body canal. The device includes a body member defining at least one therapeutic treatment material receiving chamber and at least one resilient arm member associated with the body member for removably engaging the body canal when the device is positioned therein.

TECHNICAL FIELD

The present invention relates to a device for applying a therapeutictreatment to a selected portion of the body and, more particularly, toan improved device for applying therapeutic radiation by beingtransported into a body orifice via a fiberoptic endoscope to apredetermined portion thereof.

BACKGROUND ART

In the United States there are presently over 100,000 deaths per yearresulting from bronchial carcinoma or lung cancer. Conventionaltreatments for lung cancer include surgery, radiation therapy andchemotherapy. Although the surgical removal of a malignant lung tissueremains as the effective method of choice of physicians, it may only beaccomplished in a few early cases before intrathoracic or distant spreadof the tumor has taken place. Radiation therapy by external beam hasbeen found to be of limited value in prolonging the life of a patientwith the disease even with doses in the range of 5,000 to 6,000 rads inview of the inability to control the irradiated tumor and a highincidence of distant metastases.

Interstitial irradiation has been shown to be promising for the localtreatment of certain tumors assuming that the dose rate of radiationdelivered from a stereotoxically implanted source is sufficiently highthat tumor cells receive a critical threshold dose during a completecell cycle. This condition can be met by using high-activityradioisotopes which can be removed from the site after the dose isdelivered thereto. If the high-activity radioisotope were to remainimplanted, normal tissue surrounding the radioactive source would beexposed to potentially toxic doses of radiation. It is known to utilizeremovable radioactive sources encased within catheters made to preciselyhold the radioactive source at the tumor target site. An improvement inthis art is disclosed in U.S. Pat. No. 4,584,991 to Tokita, et al.

In view of shortcomings presented by the present state of the radiationtherapy art, applicant has developed an inventive implant capsule forradioisotopes which is adapted to be remotely implanted and retrieved bymeans of a catheter inserted through the collateral lumen of afiberoptic bronchoscope. The capsule possesses resilient engaging meansto enable the implant device to engage the bronchial walls when releasedat a predetermined location for treatment of a bronchial malignancy. Theimplant capsule has application to other organs and other types ofendoscopes and may also be used for endoscopic drug delivery by placinga chemotherapeutic agent therein for localized or topical chemotherapytreatment.

DISCLOSURE OF THE INVENTION

In accordance with the present invention, applicant provides atransendoscopic implant capsule adapted to be transported through a bodycavity or passageway in order to apply a therapeutic radiation orchemotherapeutic treatment to a tumor or a malignant area within thebody. The implant capsule comprises a body member defining one or moreelongate treatment material receiving chambers therein and one or moreresilient arm members cooperatively associated with the body member andextending generally radially outwardly therefrom. In this fashion thearm members may be radially compressed inwardly during transportation ofthe implant capsule to a selected portion of the body requiringtherapeutic treatment and then released in order that the arm membersmay return to its outwardly extending position in order to engage thebody portion and thereby retain the capsule in place.

Accordingly, it is an object of the device of the invention to providean improved implant capsule of type adapted to contain a radioactivetherapeutic treatment for point-source localized radiotherapy.

A further object of the present invention is to provide an implantcapsule for application of radiotherapy or chemotherapy treatment whichis adapted to be remotely implanted and retrieved with a fiberopticbronchoscope.

A still further object of the present invention is to provide an implantcapsule adapted for containing a selected number of radioisotope seedsfor radiotherapy which can be remotely implanted and retrieved with afiberoptic bronchoscope and which is further adapted to engage the bodyportion with resilient arms when implanted therein.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the objects of the invention having been stated, other objectswill become evident as the description proceeds, when taken inconnection with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a preferred embodiment of theimplant capsule of the present invention;

FIG. 1A is a view of the body member of the present invention takenalong line 1A--1A of FIG. 1;

FIG. 2 is a side elevation view of the implant capsule shown in FIG. 1with the resilient arm members fully extended;

FIG. 3 is a side elevation of the implant capsule of FIG. 1 with theresilient arm members fully collapsed within the body member thereof;

FIG. 4 is a perspective view of a second embodiment of the implantcapsule of the present invention comprising a shortened body member;

FIG. 5 is a perspective view of a third embodiment of the implantcapsule of the present invention comprising a shortened body member anda flexible central stem from which the arm members extend; and

FIG. 6 is a perspective view of another embodiment of the implantcapsule of the present invention wherein the body member comprises asingular flexible elongate chamber.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now generally to the drawings, several different embodimentsof an implant capsule of the present invention are depicted whichcomprise a body member defining at least one elongate therapeutictreatment material receiving chamber therein to hold radioisotope seedsor a chemotherapeutic agent and resilient arm members to restrainmovement of the capsule when properly positioned within the body. Theimplant capsule's resilient arm members are designed to have maximumstored spring energy per unit length in order to minimize the requiredsize of the capsule when retracted and released using an externalcatheter and forceps which can be introduced through a fiberopticbronchoscope. A standard biopsy-type forcep modified to grasp thespherical tip of the stem of the resilient arm members may be utilizedwithin a sheath to retract the resilient arm members by sliding thesheath thereover and later to extend them by removing the sheath.Although the use of a catheter or sheath with a slidably movable biopsyforcep therein is presently contemplated as the preferred type ofinstrument to manipulate the implant capsule of the present invention,other manipulation means are clearly possible.

Referring now specifically to FIGS. 1-3, there is illustrated apreferred embodiment, generally designated 10, of the implant capsule ofthe invention for applying therapeutic radiation to a selected portionof the body. Implant capsule 10 consists of body member 12 which definesa plurality of chambers 14 therein adapted to receive a therapeutictreatment material such as radioisotope seeds and/or chemotherapeuticagents. The use of both a radioactive isotope and a chemotherapeuticmaterial is known to have a synergistic effect in the treatment ofcancer, and the use of both in capsule 10 may be desirable. Body member12 also defines a plurality of radially extending slots 16, as best seenin FIGS. 1 and 1A. Resilient arm members 18 are secured to central stem20 and adapted to be slidably received by the bore 22 (see FIG. 1A) andslots 16 within body member 12. The face of body member 12, as bestillustrated in FIG. 1A, illustrates that bore 22 extends along thelength of body member 12 and terminates with a relatively small diameteraperture 24 at the remote end thereof. Central stem 20 is receivedwithin body member 12 so that the end portion thereof (opposite sphere26) extends through aperture 24 and cap 28 so that E-clip 30 may besecured to groove 32 of the stem in order to assure a snug fit of bodymember 12, cap 28 and central stem 20 after a treatment material isplaced within chamber 14. Although a matter of design choice, chambers14 will accommodate up to 28 radioactive isotope units and/orchemotherapeutic agent boluses in the preferred embodiment of theinvention illustrated in FIGS. 1-3. Arm members 18 are most suitablyfabricated from a special alloy wire (such as MP 35N manufactured byMaryland Specialty Wire Company) having a tensile strength of at least300,000 psi. and which is compatible with body tissues and fluids.Central stem 20 can be stainless steel or other compatible metal and armmembers 18 are attached thereto by a suitable method of fixation such aselectric fusion welding. Body member 12 and cap 28 are fabricated from abiocompatible plastic material.

As best seen in FIGS. 2 and 3, in clinical usage a grasping forcep 34within catheter 36 would be inserted through the collateral lumen at theproximal end of a bronchoscope (not shown) and passed therethrough toengage sphere 26 of implant capsule 10 at the remote or distal end ofthe bronchoscope. Flexible sheath or catheter 36 is then extended (seeFIG. 3) into bore 22 of body member 12 so as to extend over and collapseresilient arm members 18 into slots 16. Implant capsule 10 and catheter36 positioned in the lumen of the fiber-optic bronchoscope are theninserted into a selected area of the patient's lung. Catheter 36 isretracted so as to permit resilient arm members 18 to extend outwardlythrough slots 16 and the barbs at the ends thereof to secure the capsuleto the inner bronchus wall. With this retrograde-load technique,capsules larger than the accessory lumen can be implanted and retrieved.Once the capsule has been secured, the bronchoscope and associatedforcep 34 and catheter 36 are temporarily withdrawn. After apredetermined prescribed treatment time, the bronchoscope is reinsertedinto the bronchus and the process repeated in order to retract armmembers 18 and withdraw implant capsule 10 from its location in apatient's lung.

A second embodiment of the present invention is illustrated in FIG. 4and generally designated 40. Implant capsule 40 comprises body member 42defining treatment receiving chambers 44 therein, central stem 46 withresilient arm members 48 and sphere 49, cap 50 and E-clip 52. Armmembers 48 are received by slots 53 when collapsed by catheter 36 (seeFIG. 2) into body member 42 for insertion or removal from the lung. Thisembodiment of the invention is substantially similar to that shown inFIGS. 1-3 except body member 42 only extends for a portion of the lengthof stem 46 and the chambers therein are of a shorter length thanchambers 14 of implant capsule 10. Implant capsule 40 is thereforecapable of holding fewer isotope seeds, most suitably about 8, and lessof other chemotherapeutic agents than is the capsule describedhereinbefore.

A third embodiment of the present invention is depicted in FIG. 5 andgenerally designated 60. Implant capsule 60 is similar to implantcapsule 40 but additionally provides a flexible central stem 62 to whichresilient arm members 64 are attached. Flexible central stem 62 allowsfor greater ease of manipulation or flexing of implant capsule 60 as itis moved within the lumen of a bronchoscope and can also be used tocontain a linear distribution of radioisotope seeds. The body or podmember 61 is smaller and presently contemplated to contain only about 4radioisotope seeds within the chambers defined therein (not shown).

FIG. 6 depicts still another embodiment of the implant capsule of thepresent invention, generally designated 70. Implant capsule 70 isdesigned to overcome certain limitations of the implant capsulesillustrated in FIGS. 1-5. The relatively more rigid implant capsulesdescribed above are particularly suitable for point-source radiation tocertain locations within a lung but do not lend themselves as well asimplant capsule 70 to placement in an area to be irradiated whichextends linearly or curvilinearly along a bronchus or around a cornerthereof. For these particular types of applications, implant capsule 70is particularly appropriate since it comprises a linear flexible bodymember 72, most suitably constructed of a flexible plastic, whichdefines a singular chamber therein for receiving a linear array ofradioisotope seeds. A sphere 74 with radially extending arms 76 securedthereto (to facilitate grasping of the sphere by forceps 34) is attachedto one end of linear body member 72, and arm members 78 secured to stem80 are attached at the other end thereof to engage the bronchus wall. Itshould be observed that the hooks of arm members 76 extend inwardly inorder to allow catheter 36 to extend thereover and slidably receiveimplant capsule 70 therein for placement or removal from a selectedlocation in a lung. It should also be noted that the small diameter ofimplant capsule 70 can permit insertion directly through thebronchoscope without the requirement of retrograde loading as forcapsules described hereinbefore.

Although the implant capsules of the present invention have beendiscussed primarily in terms of a containment vessel for radioisotopeseeds, chemotherapeutic agents, as noted hereinbefore, are alsocontemplated to be placed therein for localized or topical chemotherapytreatment. Though not illustrated in the drawings, the chemotherapeuticagent could be placed within an implant capsule of the present inventionand released through a contact wick system, semi-permeable membrane orthe like into adjacent tissue.

It will be understood that various details of the invention may bechanged without departing from the scope of the invention. Furthermore,the foregoing description is for the purpose of illustration only, andnot for the purpose of limitation -- the invention being defined by theclaims.

What is claimed is:
 1. A device for applying a therapeutic treatment toa selected portion of a body for a predetermined period of timecomprising:a body member defining at least two elongate therapeutictreatment material receiving chamber means for receiving a radiotherapytreatment agent; a plurality of retractable resilient arm memberscarried by said body member and extending generally radially outwardlytherefrom, said arm members being adapted to be compressed radiallyinwardly into groove means defined by said body member for receivingsame during transportation of the device to a portion of the bodyrequiring therapeutic treatment and to then be released so as to allowsaid arm members to return their position extending outwardly from saidbody member in order to engage the body portion and to apply thetherapeutic treatment thereto; and means for attaching an instrument forinserting and removing said device.
 2. A device according to claim 1wherein said body member defines at least two substantially paralleltreatment receiving chamber means for receiving said radiotherapytreatment agent.
 3. A device according to claim 1, further including acentral stem wherein said plurality of resilient arm members extendoutwardly from said central stem, said central stem being concentricallysecured to said body member and extending substantially parallel to saidtreatment material receiving chamber means.
 4. A device according toclaim 3 wherein said plurality of arm members each comprises an endportion turned back on itself to define a barb.
 5. A device according toclaims 2 or 3 wherein said body member is coextensive with one end ofsaid central stem.
 6. A device according to claims 2 or 3 wherein saidbody member is coextensive with substantially the entire length of saidcentral stem.
 7. A device according to claim 1 wherein said body memberis adapted to receive one or more radioisotope seeds within each of saidat least two therapeutic treatment material receiving chamber means. 8.A device according to claim 1 wherein said body member is adapted toreceive a chemotherapeutic agent within each of said at least twotherapeutic treatment material receiving chamber means.
 9. A deviceaccording to claim 1 wherein said body member is adapted to receive achemotherapeutic agent and a radioactive isotope within said at leasttwo therapeutic treatment material receiving chamber means.